Modern mobile phones and tablets have evolved over recent years to the point where they now possess a broad range of capabilities. They are not only capable of placing and receiving mobile phone calls, multimedia messaging (MMS), and sending and receiving email, but they can also access the Internet, are GPS-enabled, possess considerable processing power and large amounts of memory, and are equipped with high-resolution color liquid crystal displays capable of detecting touch input. As such, today's mobile phones are general purpose computing and telecommunication devices capable of running a multitude of applications. For example, modern mobile phones can run web browsers, navigation systems, media players and gaming applications.
Along with these enhanced capabilities has come a demand for larger displays to provide a richer user experience. Mobile phone displays have increased in size to the point where they can now consume almost the entire viewing surface of a phone. To increase the size of displays any further would require an increase in the size of the phones themselves. This is not desirable, as users want their mobile phone to fit comfortably in their hand or in a shirt or pants pocket.
As a result, dual-display devices are becoming more popular. With a dual-display device, the mobile phone or tablet can include an open, expanded position where both displays are flush so that the user feels like there is a single integrated display. In a closed, condensed position, both displays are face-to-face so as to protect the displays. In a fully-open position, the dual displays can sit back-to-back so the user needs to flip the device to view the opposing display.
Hinges for such dual-display devices are problematic. Typically, the hinges can protrude from the device as it switches between positions. As devices continually become thinner, hinges need to be adapted to accommodate the thinner displays without further protrusion from the back of the device as it is opened and closed. Additionally, excess slack can make the two displays feel loosely connected. Other problems include that the displays do not open and close smoothly. Still yet another problem is the ability to stop the displays in any position as the displays are opened and closed. Torque or friction hinges are known and offer resistance to a pivoting motion. However, the friction hinges can be bulky and protrude from the device. Still another problem is to ensure the displays remain comfortably in the open, flush state, while the user holds one or both displays.
Therefore, it is desirable to provide improved hinges for multiple display devices.